address PR feedback

Author: ohmayr

setup.py

@@ -36,16 +36,18 @@
 
 requests_extra_require = ["requests >= 2.20.0, < 3.0.0"]
 
-aiohttp_extra_require = ["aiohttp >= 3.6.2, < 4.0.0.dev0", *requests_extra_require]
+aiohttp_extra_require = ["aiohttp >= 3.6.2, < 4.0.0", *requests_extra_require]
 
 pyjwt_extra_require = ["pyjwt>=2.0", *cryptography_base_require]
 
 reauth_extra_require = ["pyu2f>=0.1.5"]
 
+# TODO(https://github.com/googleapis/google-auth-library-python/issues/1738): Add bounds for cryptography and pyopenssl dependencies.
 enterprise_cert_extra_require = ["cryptography", "pyopenssl"]
 
 pyopenssl_extra_require = ["pyopenssl>=20.0.0", cryptography_base_require]
 
+# TODO(https://github.com/googleapis/google-auth-library-python/issues/1739): Add bounds for urllib3 and packaging dependencies.
 urllib3_extra_require = [["urllib3", "packaging"]]
 
 # Unit test requirements.